The present invention relates to the dispensing of viscous cartridge-packaged fluid materials and the like for industrial and other applications, including also dental materials such as high viscosity impression materials and also other fluid materials such as washes and crown-and-bridge materials, and the like, currently packaged in dual cartridges for hand-controlled and hand-held dispensing guns and the like.
More particularly, the invention is concerned with hand-held fluid cartridge dispensers that are electrically operated and are of the type described in my earlier U.S. Pat. No. 6,089,407, issued Jul. 18, 2000, for Electrically Powered Fluid-Dispensing Apparatus and Method Particularly Adapted For Hand gun Operation, using battery or mainsxe2x80x94power, and preferably employing rack and pinion drives for engaging push pads carried at the ends of longitudinal racks with the piston plugs or plungers of fluid-filled cartridges positioned in chambers extending longitudinally in line with and forward of the racks and terminating in a fluid dispensing orifice. Upon the expelling of the fluid from the cartridges through the dispensing orifice, a spring return retracts the racks, and new cartridges are inserted into the cartridge chamber.
While such apparatus has been found to be functionally successful in use, there are occasions, particularly with certain ranges of fluid viscosities, when more forceful and rapid return of the racks after the dispensing of the fluid from the cartridges is desirable and, indeed, required. Additionally, with the advent of different designs of longitudinal fluid-containing cartridges of standardized diameter and, more especially, different-shaped cartridge rear end mounting flanges, and, sourcing of cartridges from an expanding number of different cartridge manufacturers using widely different types of fluid materials for a myriad of different usages, the need for a universal holder mechanism for accommodating for such different-shaped cartridge end flanges has become important, to enable a single dispenser gun to accommodate all types of such cartridges.
It is to the providing of these important improvements, accordingly, that the present invention is primarily directed.
It is therefore a principal object of the present invention to provide a new and improved preferably hand dispenser apparatus for the dispensing of a wide variety of cartridge-packaged fluids and the like that shall not be subject to the above-described limitations, but, rather, shall enable rapid and positive retraction of rack push pads and universality of usage of the gun with multiple-shaped cartridge end mounting flanges.
A further object is to provide such an improved electrically powered hand-held dispenser that is particularly, though not exclusively, adapted to be used by dentists and the like.
Other and further objects will be explained hereinafter and are more particularly delineated in the appended claims.
In summary, however, the invention embraces in an electric motor-driven fluid-filled cartridge dispenser wherein longitudinal racks are driven forward within a fixed rack guide to force the fluid in the cartridges to be dispensed, apparatus having, in combination, motor, reducing and drive gears; the drive gear being adapted to move the rack longitudinally, and the motor gear being driven by an electric motor; the reducing gear being mounted to be driven when engaged by the motor gear and driving the drive gear to move the rack; a flat coil spring secured at one end to the top of the rack guide and connected at its other end to the reducing gear so as to be tensioned as the motor gear is springxe2x80x94urged into engagement with the reducing gear and drives the reducing gear, and to be released upon disengagement from the motor gear; and a spring-controlled release mechanism actuable upon the dispensing of the fluid from the cartridges for disengaging the motor gear from the reducing gear to enable the coil spring retraction of the racks longitudinally within the rack guide.
Preferred and best mode embodiments and designs are hereinafter explained in detail.